Bump Ruby to 2.3.0

.ruby-version

@@ -1 +1 @@
-2.2.2
+2.3.0

Dockerfile

@@ -1,5 +1,5 @@
 
-FROM ruby:2.2.2
+FROM ruby:2.3.0
 MAINTAINER Conor Heine <conor.heine@gmail.com>
 
 RUN apt-get update

Gemfile

@@ -1,5 +1,5 @@
 source 'https://rubygems.org'
-ruby '2.2.2'
+ruby '2.3.0'
 
 gem 'rake'
 gem 'thor'

README.md

@@ -21,7 +21,7 @@ Unless you wish to contribute to the project, I recommend using the hosted versi
 
 DevDocs is made of two separate pieces: a Ruby scraper that generates the documentation and metadata, and a JavaScript app powered by a small Sinatra app.
 
-DevDocs requires Ruby 2.2.2, libcurl, and a JavaScript runtime supported by [ExecJS](https://github.com/sstephenson/execjs#readme) (included in OS X and Windows; [Node.js](http://nodejs.org/) on Linux). Once you have these installed, run the following commands:
+DevDocs requires Ruby 2.3.0, libcurl, and a JavaScript runtime supported by [ExecJS](https://github.com/sstephenson/execjs#readme) (included in OS X and Windows; [Node.js](http://nodejs.org/) on Linux). Once you have these installed, run the following commands:
 
 ```
 git clone https://github.com/Thibaut/devdocs.git && cd devdocs

lib/app.rb

@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 require 'bundler/setup'
 Bundler.require :app